Israeli troops poured into Qalqilyah in the northern West Bank Sunday, making it the third Palestinian area in the territory to be raided in as many days. The operations come amid heightened alerts of impending Palestinian terror attacks.

Israeli soldiers swept into Qalqilya Sunday just hours after withdrawing from Bethlehem, another Palestinian self-rule town in the West Bank.

The city was placed under curfew as the troops carried out searches in what the army said was an operation aimed a foiling planned terror attacks.

The army has been sweeping in and out of Palestinian ruled towns since May 10, when it declared an end to a broader military offensive against the West Bank known as Operation Defensive Shield.

On Saturday, the Israeli army raided Bethlehem, where it arrested one suspected Palestinian militant.

And on Friday, the troops entered Tulkarem, where they rounded up four Palestinians before withdrawing the next day.

The latest series of raids follow four suicide bombings last week, including one that killed two people in the Israeli town of Rishon Lezion and another that was prevented when a security guard fired at a bomber's car as it raced towards a night club in Tel Aviv on Friday.

At least three Palestinian civilians have been reported killed during the operations.

In Tulkarm, a 50-year-old man was shot by Israeli soldiers as they advanced into a residential area.

The Israeli Army has also apologized for the deaths of a Palestinian woman and her 13-year-old daughter in the Gaza Strip. The two were mistakenly killed Saturday by soldiers who suspected they were planning an attack.